In recent years, OLEDs (Organic Light-emitting Diodes) develop rapidly, and have already technically become most possible to replace LCDs (Liquid Crystal Displays). Generally, an OLED device at least includes an anode, a cathode and an organic light-emitting layer located between the anode and the cathode. The organic light-emitting layer and electrodes in the OLED device are easily eroded by water and oxygen, so that the service life of the OLED device is greatly reduced. The encapsulation technology for the OLED device is one of the cores of the research at the present stage.
Currently, an encapsulation method of the OLED device includes attachment of getter and coating of ultraviolet (UV) adhesives, face seal, frit seal encapsulation, thin film encapsulation and the like. The frit seal encapsulation is an encapsulation method as follows: adding glass frit such as SiO2, Al2O3 and the like to other raw materials to form paste, coating the paste on an encapsulation substrate; then aligning the encapsulation substrate and an evaporated substrate with each other; and finally, sintering the frit seal by means of laser.
In the frit seal encapsulation process, when the encapsulation substrate and the evaporated substrate are aligned with each other, as shown in FIG. 1, because frit seal 5 is coated on the encapsulation substrate 4, the evaporated substrate 1 can be tightly adhered to the frit seal 5 under a certain pressure. The pressure may cause small deformation to the encapsulation substrate, and specifically, may cause the encapsulation substrate 4 to be bent, as shown in FIG. 1. However, because the thickness of the frit seal 5 is only a few microns, the encapsulation substrate 4 is pressed on the OLED device 2 due to the deformation so as to result in damage to the OLED device, thus influencing the performance of the display panel.
In order to prevent the damage to the OLED device caused by bending of the encapsulation substrate 4, A solution adopted currently is that as shown in FIG. 2, a photo spacer 3 (PS) with certain thickness is formed on the evaporated substrate 1. When the encapsulation substrate 4 is deformed (bent) due to pressure, the photo spacer 3 supports the encapsulation substrate 4 to keep the distance between the encapsulation substrate 4 and the evaporated substrate 1, thereby protecting the OLED device 2 from being damaged. At present, the photo spacer 3 is generally formed by photoetching, namely, the photo spacer is formed by a photo line formed by a series of photoetching equipments. For example, a layer of photoresist is coated on the evaporated substrate 1 by using a coating machine, then is exposed by an exposure machine, next is developed by using a developing machine and subsequently is cured by using a curing machine so that the photo spacer with certain thickness and shape is finally formed.
Since forming photo spacer by photoetching needs a lot of equipments, and particularly the exposure machine is always a bottleneck in the photoetching process, the cost is relatively high. Therefore, when a photo line is specially provided for forming a deformation-resistant photo spacer, the occupied space is large, the manufacturing cost is greatly increased, and thus the cost of the display panel and the display device is correspondingly increased. Moreover, the photoetching method is complicated in process.